Dialog management systems are a key component in building conversational systems. The closest approach to a human-machine interface is a system that has very good speech recognition and a high level natural language understanding capability. However, due to the limited accuracy of any speech recognition system, known conversational systems must exploit the knowledge of a limited context to improve on recognition accuracy.
A typical conversational system is dialog based. The system asks a question to the user. Based on the user's response, a dialog management system moves in a particular order of further questions—the dialog call-flow—until it gains enough information from the user to perform the desired action. If a user has to go through a large number of questions to complete the call flow, the comfort factor of the system will be low. Therefore, any dialog management system has to balance keeping the number of questions small and asking sufficient questions to correctly determine the user's enquiry.
When such applications are to run on pervasive computing devices, the dialog management system has to additionally take into account the limited resources (including battery power and available memory). These factors will typically constrain the duration of a call-flow or the number of dialogs.